In order to improve the traditional time domain finite difference method, the discrete method in time is consistent with the FDTD method, while in space, the discrete format with high-order accuracy is used,thereby improving the calculation accuracy of the traditional FDTD method.In this paper, the iterative formula of high-order FDTD algorithm is derived. The near-far field extrapolation technique to the high-order FDTD algorithm is introduced. Finally, the high-order FDTD method has been applied to the analysis of electromagnetic scattering properties of three-dimensional spherical media. The numerical results show that the high-order FDTD method can still achieve better accuracy when the mesh size is larger, and not only does it take less computing time, it also saves computer memory.